Pre-amp, integrated, new power amp...I'm confused


OK, after posting many threads and reading tons of old threads and reviews...I"m stumped. I have a NAD C370 integrated powering SOnus Faber COncerto's (Home Version), a Cambridge audio Azur 640C CD player going through a musical fidelity tube buffer(my one and only audio source), Cardas Cross IC's and speaker cables. A REL Stadium III handles the bottom end. I love my system, excepy for a little graininess in the top end. I would like to smooth out the sound and make it more liquid and natural. How do I best accomplish this? DO I invest in a whole new integrated? DO i Drive the power amp section of my NAD with a tube pre-amp? DO I invest in a better Source (New DAC or whole new player). I like the sound smoothe and natural...maybe a little warm (Which is why I chose SOnus speakers. I would like to spend no more than $1000. I saw a BAT VK-3i tube preamp available. Am I on the right track with that? Help!
phoenix469
Sell your integrated and buy a primaluna integrated. I think it has the sound you are describing. Well built too.
Post removed 
OK, i have decied to go the route of a new tube based preamp. That seems to make the most sense to me. I think the NAD amp section is good enough for now. I did some calculations and when I bought the NAD new, it was only $80 more than a matching NAD amp only. That probably means NAD only spent around $100 dollars on the line stage in the integrated. I don't need A phono section, because I am not going to be getting into vinyl anytime soon. I have my choices down to 3 preamps:

BAT vk3i
Rogue Magnum 99
Jolida Music Envoy preamp

Which do you people think would be a better performer?

Thanks in advance!
Post removed 
To add to your confusion, I would suggest a simple solution.

*Park the MF buffer.
*Purchase a nice used integrated for ~800 or less -- many here at Agon (vintage Acuphase, Nuforce, Krell, A-Analogue, Opera, Simaudio, Pathos -- even a diy gainclone...).
*Connect the cdp directly to the integrated using single core wire (solid conductors - not stranded) -- take yr pick on that there's many around, and they're generally inexpensive. You can even get gold-plated silver wire

Take Tvad's advice: you don't NEED separate preamplification, but you may need a little bit of power.

OR, coming to think of it, hook the cdp directly to yr amp now. Check out the differences if any. COnnect a tuner (borrow one). Check the sound.
And come back to us.